JP2834212B2 - Magnetic probe - Google Patents
Magnetic probeInfo
- Publication number
- JP2834212B2 JP2834212B2 JP23279989A JP23279989A JP2834212B2 JP 2834212 B2 JP2834212 B2 JP 2834212B2 JP 23279989 A JP23279989 A JP 23279989A JP 23279989 A JP23279989 A JP 23279989A JP 2834212 B2 JP2834212 B2 JP 2834212B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- probe
- sample
- coating layer
- information
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
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- Measuring Magnetic Variables (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Description
本発明は，探針と試料，特に磁性探針と磁性試料とを
接近して発生する磁気力およびトンネル電流を利用する
装置に係り，試料の表面形態と磁気的性質の情報を得る
のに好適な走査型磁気力顕微鏡および走査型トンネル顕
微鏡あるいは原子間力顕微鏡もしくはその類似装置に用
いる磁性探針の構造に関する。The present invention relates to an apparatus using a magnetic force and a tunnel current generated when a probe and a sample, particularly a magnetic probe and a magnetic sample, approach each other, and is suitable for obtaining information on the surface morphology and magnetic properties of the sample. The present invention relates to the structure of a magnetic probe used for a scanning magnetic force microscope, a scanning tunneling microscope, an atomic force microscope, or a similar device.
走査型トンネル顕微鏡は，探針と試料間に電圧を印加
し，探針と試料との距離を接近したときに得られるトン
ネル電流および電界放射電流を利用して試料の表面形態
を調べる装置である。一方，走査型磁気力顕微鏡は，探
針として磁性体を用い，この磁性探針を磁性試料に接近
したときの磁気力を利用して試料の磁化状態を調べる装
置である。 従来，磁性探針と試料を接近して得られる磁気力を利
用した走査型磁気顕微鏡における試料の磁気的情報の取
得方法については，ジャーナル オブ バキューム サ
イエンス テクノロジーA6（1988年）第279頁から第282
頁，あるいはアプライド フィジックス レターズ 50
巻（1987年）第1455頁から第1457頁において論じられて
いる。A scanning tunneling microscope is a device that applies a voltage between a probe and a sample and examines the surface morphology of the sample using tunnel current and field emission current obtained when the distance between the probe and the sample is reduced. . On the other hand, a scanning magnetic force microscope is an apparatus that uses a magnetic material as a probe and uses a magnetic force when the magnetic probe approaches a magnetic sample to check the magnetization state of the sample. Conventionally, a method of acquiring magnetic information of a sample in a scanning magnetic microscope using a magnetic force obtained by bringing a magnetic probe and a sample close to each other has been described in Journal of Vacuum Science Technology A6 (1988) pp. 279-282.
Pages or Applied Physics Letters 50
Volume (1987), pp. 1455--1457.
上記従来技術で用いる磁性探針は，ニッケル（Ni）や
鉄（Fe）の細線が一般的に用いられ，これらは長時間の
動作中あるいは動作雰囲気などにより磁性針の表面が磁
化などにより変質して磁性探針の磁気特性が変わり，計
測の再現性に問題があった。また，従来の測定手段では
磁気力と表面形態とを同時に測定していないため，探針
と試料との間隙の変化による誤差が入り，正確な磁気力
の測定ができないという欠点があった。さらに磁性針表
面に酸化膜等が形成されると，試料と探針間のトンネル
電流が不安定になり、良好な試料表面の観察ができない
という問題があった。 本発明の目的は，磁性探針表面の変質を防止し，試料
と探針間の磁気力とトンネル電流を再現性良く測定でき
る磁性探針を提供することにある。The magnetic probe used in the above-mentioned conventional technology is generally a thin wire made of nickel (Ni) or iron (Fe), and the surface of the magnetic needle is deteriorated due to magnetization or the like during long-time operation or operating atmosphere. As a result, the magnetic properties of the magnetic probe changed, and there was a problem in the reproducibility of the measurement. In addition, since the conventional measuring means does not measure the magnetic force and the surface morphology at the same time, there is an error due to a change in the gap between the probe and the sample, so that there is a disadvantage that the magnetic force cannot be measured accurately. Further, if an oxide film or the like is formed on the surface of the magnetic needle, there is a problem that tunnel current between the sample and the probe becomes unstable, and good observation of the sample surface is not possible. An object of the present invention is to provide a magnetic probe capable of preventing deterioration of the surface of a magnetic probe and measuring a magnetic force and a tunnel current between a sample and the probe with good reproducibility.
上記目的を達成するために、本発明においては磁性針
の表面に被覆層を形成した。 カンチレバーの先端部に設置した先端が鋭く尖った磁
性探針を磁性試料表面に接近すると磁性試料表面の漏れ
磁界の向きに対応して，試料と磁性探針の間に引っ張り
あるいは反発力が働き，その結果，カンチレバーに撓み
が生じる。この撓みの量をカンチレバーの後方に設置し
た変位検出手段（例えばトンネル電流を検出する方法，
光学的な方法）により，磁性試料の磁気的情報を得るこ
とができる。しかしこの磁気的情報には試料表面の形態
情報も含まれているため，同時に試料と磁性探針の間の
トンネル電流を測定することにより，試料表面の形態情
報を得ることができるので，上記２つの情報からより正
確な試料の磁気的情報を求めることができる。 同様の計測手段は，試料と探針の間の磁気力の他に，
音響，熱，光などによる試料と探針間の変位を検出する
走査型トンネル顕微鏡類似装置に適用できる。 以上述べた手段により，試料の磁気力情報と表面形態
情報を再現性良く得るには，磁性探針は次の条件を満た
す必要がある。磁性探針としては，一般にNiやFeからな
る材料の先端を鋭く研磨して用いられるが，これらの材
料は酸化し易く，材料の一部が酸化などにより変質する
と，飽和酸化や保磁力，あるいは磁気異方性等が変化す
る。また磁性探針の表面が酸化すると，試料と磁性探針
の間の電気抵抗が増大し，このトンネル電流が流れにく
くなる。このため，試料の磁気力情報や表面形態情報を
再現性良く得るために，測定時の雰囲気や測定時間の経
過などにより，磁性探針の磁気特性が変化しないことが
必要である。このためには測定時の雰囲気や測定時間の
経過とともに磁性探針の表面が酸化などにより変質させ
ないような対策が必要である。 本発明では，上記目的のために，磁性探針の表面に磁
性探針の材料に比べて酸化力の小さい材料からなる被覆
層を形成した。この被覆層はNi,Fe,Co,希土類元素，あ
るいはこれらを含む材料からなる磁性探針の表面に酸化
膜や窒化膜などの辺質層が形成して，磁性探針の磁気的
性質の変化を防止する作用をする。 この被覆層の材料として望ましい材料は,Pt,Pd,Au,R
u,Rhおよび，これらの内の少なくとも一元素を含む合金
である。またこの被覆層の望ましい厚さは,100nm以下で
ある。また被覆層の材料としては電気伝導性を有する材
料が望ましい。さらに望ましくは非磁性の材料がよい。 すなわち，磁性探針の表面に被覆層を形成することに
より，試料表面の磁気力情報と表面形態情報を同時に再
現性良く測定することを可能にするものである。In order to achieve the above object, a coating layer is formed on the surface of the magnetic needle in the present invention. When a sharply pointed magnetic probe set at the tip of the cantilever approaches the magnetic sample surface, a pull or repulsive force acts between the sample and the magnetic probe in accordance with the direction of the leakage magnetic field on the magnetic sample surface. As a result, the cantilever is bent. Displacement detecting means (for example, a method for detecting a tunnel current,
(Optical method), magnetic information of the magnetic sample can be obtained. However, since the magnetic information includes the morphological information of the sample surface, the morphological information of the sample surface can be obtained by simultaneously measuring the tunnel current between the sample and the magnetic probe. More accurate magnetic information of the sample can be obtained from the two information. A similar measuring means, besides the magnetic force between the sample and the probe,
The present invention can be applied to a scanning tunnel microscope-like device that detects displacement between a sample and a probe due to sound, heat, light, or the like. In order to obtain magnetic force information and surface morphological information of a sample with good reproducibility by the means described above, the magnetic probe must satisfy the following conditions. Generally, the tip of a material made of Ni or Fe is sharply polished and used as a magnetic probe. However, these materials are easily oxidized, and when a part of the material is altered by oxidation or the like, saturation oxidation, coercive force, or The magnetic anisotropy changes. Also, when the surface of the magnetic probe is oxidized, the electric resistance between the sample and the magnetic probe increases, and it becomes difficult for this tunnel current to flow. Therefore, in order to obtain the magnetic force information and the surface morphology information of the sample with good reproducibility, it is necessary that the magnetic characteristics of the magnetic probe do not change due to the atmosphere at the time of measurement or the lapse of the measurement time. For this purpose, it is necessary to take measures to prevent the surface of the magnetic probe from being deteriorated due to oxidation or the like as the atmosphere or the measurement time elapses during the measurement. In the present invention, for the above purpose, a coating layer made of a material having a lower oxidizing power than the material of the magnetic probe is formed on the surface of the magnetic probe. This coating layer changes the magnetic properties of the magnetic probe by forming an oxide or nitride film on the surface of the magnetic probe made of Ni, Fe, Co, rare earth elements, or materials containing these elements. Acts to prevent. Preferred materials for the coating layer are Pt, Pd, Au, R
u, Rh, and alloys containing at least one of these elements. The desirable thickness of this coating layer is less than 100 nm. Further, a material having electric conductivity is desirable as a material of the coating layer. More preferably, a nonmagnetic material is used. That is, by forming a coating layer on the surface of the magnetic probe, it is possible to simultaneously measure the magnetic force information and the surface morphological information on the sample surface with good reproducibility.
以下、本発明の実施例を説明する。 実施例１ 第１図により，本実施例を説明する，フォトプロセス
によりカンチレバー１と磁性針２を作製する。すなわ
ち,Si基板の表面を酸化させ、厚さ1.5μｍのSiO2の膜を
形成する。次にフォトプロセスにより幅20μm,長さ200
μｍにパターニングする。続いて上記SiO2膜の先端部に
磁性針２を形成する。磁性探針の材料は80at％Ni−Feパ
ーマロイ合金とした。磁性探針は底面の直径３μm,高さ
２μm,先端の曲率約1000Åとする。この後,Si基板の一
部をエッチングにより除去して,SiO2からなるカンチレ
バー１を作製する。 磁性針２の表面に被覆層３として，厚さ100ÅのPt膜
を形成する。またカンチレバー１の裏面，すなわち金属
探針４に対向する面に導電膜５を形成する。金属探針４
は，先端が鋭く尖ったＷ線で形成する。 上記のごとく作製した磁性針2,カンチレバー1,および
金属探針４を第１図のごとくホルダー６に固定し，さら
に磁性材料からなる測定試料７と対向して設置する。 以上の構成により，磁性試料７の表面における漏洩磁
界によるカンチレバーの変位を検出し，この結果より磁
性試料７の磁区構造などの磁気力情報を得る。また同時
に磁性針２と試料７の間のトンネル電流を検出すること
により，試料表面の形態情報を得る。磁性探針の表面に
被覆層を形成することにより，空気中や真空中，あるい
は各種ガス雰囲気で長時間動作しても，再現性の良い測
定できた。 磁性針２の材料としては，パーマロイ合金の他にNi,F
e,Coおよびこれを含む合金,Co−Nb−Zr,Co−Mo−Zr,Co
−Ta−Zrなどの非晶質合金，あるいはFe/C,Fe/パーマロ
イ多層膜を用いても同様の効果を得る。被覆層３として
は,Ptの他にRu,Rh,Au,Pdおよびこれを含む合金を用いて
も効果は同じである。 実施例２ 第１図において，カンチレバー１と磁性針２を直径50
μm,長さ150μｍのNi線で構成する。すなわち，直径10
μm,長さ100μｍのNi線の先端から約10μｍの位置でＬ
字型に折り曲げ,L字型の先端を電界研磨により曲率約10
00Åに尖らせ，これにより第１図におけるカンチレバー
１と磁性針２に対応させる。続いて上記Ｌ字型のNi線の
部分にAu−Pdを約100Åの厚さ蒸着して被覆層を形成す
る。比較のために前記被覆層を設けないNi線を作製す
る。 上記２種類のNi線を用い，第１図と同様の構成で磁性
試料の磁化力情報と表面形態情報を約２週間の間に50回
繰返し測定した。その結果，被覆層を形成したNi線を用
いた場合,5％の誤差範囲内でほぼ再現性良いデータが得
られた。一方，被覆層のないNi線を用いた場合,Ni線の
先端部が酸化して磁気特性が変化し，またこれによりト
ンネル電流の変動が生じて，約20％の測定誤差が現れ
た。 Niの代わりにFeを用いた場合，被覆層の効果はさらに
顕著であった。Hereinafter, embodiments of the present invention will be described. Embodiment 1 Referring to FIG. 1, a cantilever 1 and a magnetic needle 2 are manufactured by a photo process, which explains this embodiment. That is, the surface of the Si substrate is oxidized to form a 1.5 μm thick SiO 2 film. Next, by photo process, width 20μm, length 200
Pattern to μm. Subsequently, a magnetic needle 2 is formed at the tip of the SiO 2 film. The material of the magnetic probe was an 80 at% Ni-Fe permalloy. The magnetic probe has a bottom diameter of 3 μm, a height of 2 μm, and a tip curvature of about 1000 °. Thereafter, a part of the Si substrate is removed by etching to produce a cantilever 1 made of SiO 2 . A Pt film having a thickness of 100 ° is formed as a coating layer 3 on the surface of the magnetic needle 2. Further, a conductive film 5 is formed on the back surface of the cantilever 1, that is, on the surface facing the metal probe 4. Metal probe 4
Is formed by a sharply pointed W line. The magnetic needle 2, cantilever 1, and metal probe 4 manufactured as described above are fixed to a holder 6 as shown in FIG. 1, and further placed facing a measurement sample 7 made of a magnetic material. With the above configuration, the displacement of the cantilever due to the leakage magnetic field on the surface of the magnetic sample 7 is detected, and magnetic force information such as the magnetic domain structure of the magnetic sample 7 is obtained from the result. At the same time, by detecting the tunnel current between the magnetic needle 2 and the sample 7, the morphological information of the sample surface is obtained. By forming a coating layer on the surface of the magnetic probe, it was possible to measure with good reproducibility even when operated for a long time in air, vacuum, or various gas atmospheres. The material of the magnetic needle 2 is Ni, F in addition to the permalloy alloy.
e, Co and alloys containing them, Co-Nb-Zr, Co-Mo-Zr, Co
The same effect can be obtained by using an amorphous alloy such as -Ta-Zr or a Fe / C or Fe / permalloy multilayer film. The same effect can be obtained by using Ru, Rh, Au, Pd and an alloy containing them in addition to Pt as the coating layer 3. Example 2 In FIG. 1, the cantilever 1 and the magnetic needle 2 were connected to each other with a diameter of 50.
It is composed of a Ni wire of μm and length of 150 μm. That is, diameter 10
at about 10 μm from the tip of a Ni wire of 100 μm length and 100 μm length.
Bend into L-shape, and curvature of the L-shaped tip is about 10 by electric field polishing.
In this manner, the cantilever 1 and the magnetic needle 2 shown in FIG. Subsequently, Au-Pd is deposited to a thickness of about 100 ° on the L-shaped Ni wire to form a coating layer. For comparison, a Ni wire without the coating layer is prepared. Using the two types of Ni wires, magnetizing force information and surface morphological information of the magnetic sample were measured 50 times repeatedly in about two weeks with the same configuration as in FIG. As a result, when the Ni wire with the coating layer was used, data with almost reproducibility was obtained within an error range of 5%. On the other hand, when a Ni wire without a coating layer was used, the tip of the Ni wire was oxidized and the magnetic properties changed, and this caused fluctuations in the tunnel current, resulting in a measurement error of about 20%. When Fe was used instead of Ni, the effect of the coating layer was even more remarkable.
以上述べたごとく本発明によれば，磁気力顕微鏡，お
よび類似装置における磁性探針の表面を非磁性でかつ導
電性材料からなる被覆層で被覆することにより，磁性探
針の表面の酸化などによる磁気特性の変化や電気伝導性
の変化を防止でき，磁気力情報と試料表面形態情報を再
現性良く得られる効果を有する。As described above, according to the present invention, the surface of a magnetic probe in a magnetic force microscope or a similar device is coated with a coating layer made of a non-magnetic and conductive material, thereby oxidizing the surface of the magnetic probe. A change in magnetic properties and a change in electrical conductivity can be prevented, and the effect of obtaining magnetic force information and sample surface morphology information with good reproducibility is obtained.
第１図は，本発明の一実施例の磁性探針の側面図であ
る。 符号の説明 １……カンチレバー、２……磁性針、３……被覆層 ４……金属探針、５……導電膜、６……ホルダー ７……試料FIG. 1 is a side view of a magnetic probe according to one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Cantilever, 2 ... Magnetic needle, 3 ... Coating layer 4 ... Metal probe, 5 ... Conductive film, 6 ... Holder 7 ... Sample
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭64−43777（ＪＰ，Ａ) 特開 昭63−182501（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) G01N 37/00 ＪＩＣＳＴファイル（ＪＯＩＳ) ＷＰＩ／Ｌ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-64-43777 (JP, A) JP-A-63-182501 (JP, A) (58) Fields investigated (Int. Cl. 6 , DB name) G01N 37/00 JICST file (JOIS) WPI / L
Claims (2)
を保持するカンチレバーとを有してなる磁性探針におい
て、上記磁性針の表面に被覆層を形成してなることを特
徴とする磁性探針。1. A magnetic probe comprising a magnetic needle having a sharp tip and a cantilever holding the magnetic needle, wherein a coating layer is formed on the surface of the magnetic needle. Magnetic probe.
る特許請求の範囲第１項記載の磁性探針。2. The magnetic probe according to claim 1, wherein said coating layer is conductive.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23279989A JP2834212B2 (en) | 1989-09-11 | 1989-09-11 | Magnetic probe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23279989A JP2834212B2 (en) | 1989-09-11 | 1989-09-11 | Magnetic probe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0396857A JPH0396857A (en) | 1991-04-22 |
| JP2834212B2 true JP2834212B2 (en) | 1998-12-09 |
Family
ID=16944941
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23279989A Expired - Fee Related JP2834212B2 (en) | 1989-09-11 | 1989-09-11 | Magnetic probe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2834212B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100363752C (en) * | 2004-09-03 | 2008-01-23 | 清华大学 | Horizontal Tunneling Magnetometer |
-
1989
- 1989-09-11 JP JP23279989A patent/JP2834212B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100363752C (en) * | 2004-09-03 | 2008-01-23 | 清华大学 | Horizontal Tunneling Magnetometer |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0396857A (en) | 1991-04-22 |
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| LAPS | Cancellation because of no payment of annual fees |